R help - Jan 2005 - output from table() in matrix form

Hi

How do I get the output from table() in matrix form?

If I have

R>  table(c(1,1,1,1,2,20))

  1  2 20
  4  1  1

I want

      [,1] [,2] [,3]
[1,]    1    2   20
[2,]    4    1    1


The problem is that names(table) is a vector of characters and I need 
the numeric values.

I am using

R>  rbind(as.integer(names(x)),x)




I thought tabulate() might be better as it takes an integer-valued 
vector, but it isn't
quite right because the default bins are 1:20 and  I don't want the 
zeroes.

The following is a little clunky:

R> x <- rbind(1:20,tabulate(c(1,1,1,1,2,20)))
R> x[,x[2,]>0]
      [,1] [,2] [,3]
[1,]    1    2   20
[2,]    4    1    1


Is there a better way?   It seems inelegant to coerce a character 
vector back to integers,
but OTOH  it's wasteful to have 20 bins when I only need 3.  My real 
application would have
maybe a dozen distinct (prime) integers in the range 2 up to about  1e4.





--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743

Hi Robin,

does this help:

x <- table(c(1,1,1,1,2,20))
matrix(c(as.numeric(names(x)), x), ncol=length(x), byrow=TRUE, 
dimnames=NULL)

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "Robin Hankin" <r.hankin at soc.soton.ac.uk>
To: <R-help at stat.math.ethz.ch>
Sent: Wednesday, January 05, 2005 1:18 PM
Subject: [R] output from table() in matrix form

> Hi
>
> How do I get the output from table() in matrix form?
>
> If I have
>
> R>  table(c(1,1,1,1,2,20))
>
>  1  2 20
>  4  1  1
>
> I want
>
>      [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
>
>
> The problem is that names(table) is a vector of characters and I 
> need the numeric values.
>
> I am using
>
> R>  rbind(as.integer(names(x)),x)
>
>
>
>
> I thought tabulate() might be better as it takes an integer-valued 
> vector, but it isn't
> quite right because the default bins are 1:20 and  I don't want the 
> zeroes.
>
> The following is a little clunky:
>
> R> x <- rbind(1:20,tabulate(c(1,1,1,1,2,20)))
> R> x[,x[2,]>0]
>      [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
>
>
> Is there a better way?   It seems inelegant to coerce a character 
> vector back to integers,
> but OTOH  it's wasteful to have 20 bins when I only need 3.  My real 
> application would have
> maybe a dozen distinct (prime) integers in the range 2 up to about 
> 1e4.
>
>
>
>
>
> --
> Robin Hankin
> Uncertainty Analyst
> Southampton Oceanography Centre
> European Way, Southampton SO14 3ZH, UK
>  tel  023-8059-7743
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
>

[This email is either empty or too large to be displayed at this time]

You probably want something like:
> t1 <- table( x )
> t1
x
 1  2 20 
 3  2  1 
> t2 <- rbind( as.numeric( names( t1 ) ), t1 )
> t2
   1 2 20
   1 2 20
t1 3 2  1
> dimnames( t2 ) <- NULL
> t2
     [,1] [,2] [,3]
[1,]    1    2   20
[2,]    3    2    1
> 
Bendix 
----------------------
Bendix Carstensen
Senior Statistician
Steno Diabetes Center
Niels Steensens Vej 2
DK-2820 Gentofte
Denmark
tel: +45 44 43 87 38
mob: +45 30 75 87 38
fax: +45 44 43 07 06
bxc at steno.dk
www.biostat.ku.dk/~bxc
----------------------

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Robin Hankin
> Sent: Wednesday, January 05, 2005 1:18 PM
> To: R-help at stat.math.ethz.ch
> Subject: [R] output from table() in matrix form
> 
> 
> Hi
> 
> How do I get the output from table() in matrix form?
> 
> If I have
> 
> R>  table(c(1,1,1,1,2,20))
> 
>   1  2 20
>   4  1  1
> 
> I want
> 
>       [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
> 
> 
> The problem is that names(table) is a vector of characters and I need 
> the numeric values.
> 
> I am using
> 
> R>  rbind(as.integer(names(x)),x)
> 
> 
> 
> 
> I thought tabulate() might be better as it takes an integer-valued 
> vector, but it isn't
> quite right because the default bins are 1:20 and  I don't want the 
> zeroes.
> 
> The following is a little clunky:
> 
> R> x <- rbind(1:20,tabulate(c(1,1,1,1,2,20)))
> R> x[,x[2,]>0]
>       [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
> 
> 
> Is there a better way?   It seems inelegant to coerce a character 
> vector back to integers,
> but OTOH  it's wasteful to have 20 bins when I only need 3.  My real 
> application would have
> maybe a dozen distinct (prime) integers in the range 2 up to 
> about  1e4.
> 
> 
> 
> 
> 
> --
> Robin Hankin
> Uncertainty Analyst
> Southampton Oceanography Centre
> European Way, Southampton SO14 3ZH, UK
>   tel  023-8059-7743
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list 
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read 
> the posting guide! http://www.R-project.org/posting-guide.html
>

table works the way it does because it applies to *factors*, so the names 
are the factor levels of the argument after conversion.  So if anything is 
wasteful, that is.

How about using the guts of factor and table, via

xx <- unique(x)
rbind(vals=xx, cnts=tabulate(match(x, xx)))

?

On Wed, 5 Jan 2005, Robin Hankin wrote:
> Hi
>
> How do I get the output from table() in matrix form?
>
> If I have
>
> R>  table(c(1,1,1,1,2,20))
>
> 1  2 20
> 4  1  1
>
> I want
>
>     [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
>
>
> The problem is that names(table) is a vector of characters and I need the 
> numeric values.
>
> I am using
>
> R>  rbind(as.integer(names(x)),x)
>
>
>
>
> I thought tabulate() might be better as it takes an integer-valued vector, 
> but it isn't
> quite right because the default bins are 1:20 and  I don't want the
zeroes.
>
> The following is a little clunky:
>
> R> x <- rbind(1:20,tabulate(c(1,1,1,1,2,20)))
> R> x[,x[2,]>0]
>     [,1] [,2] [,3]
> [1,]    1    2   20
> [2,]    4    1    1
>
>
> Is there a better way?   It seems inelegant to coerce a character vector
back
> to integers,
> but OTOH  it's wasteful to have 20 bins when I only need 3.  My real 
> application would have
> maybe a dozen distinct (prime) integers in the range 2 up to about  1e4.
>
>
>
>
>
> --
> Robin Hankin
> Uncertainty Analyst
> Southampton Oceanography Centre
> European Way, Southampton SO14 3ZH, UK
> tel  023-8059-7743
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595